In a 2007 Entertainment Weekly oral history of the series, star LeVar Burton, who played Geordi La Forge, shared they all hated wearing those spandex Starfleet uniforms.
"We hated our space suits," Burton said, "As much as they call it a stretch fabric, spandex in that configuration doesn't give all that much. It hid nothing."
Designed by William Ware Theiss, Stewart said the costumes were intentionally cut "one size too small so that they never wrinkled and kept our bodies on constant display."
Series creator Gene Roddenberry was notorious for what Stewart calls "cheesecake," which is to say that he loved to put his stars on a kind of salacious display.